To the best of my knowledge Samsung Kies will not work with the Google Nexus 6, since its a Samsung based product/app.
Contacts and photo's if they are linked/sync'd to your Gmail account you can transfer those easily all you need is the S2 connected WiFi to the internet to do this. You could also make an export file of your contacts, should be an option in the settings of your Contacts app then just transfer it off your device or email it to yourself.
Data.. Not too sure what you would like to transfer there but there are some options like Helium and MyBackup app's that maybe of some help there.
Personally if it was me I would limit the amount of stuff you transfer over from an existing device. Keep it to the basics like contacts and some pics but the more " pure " or clean the new device is the less chances you will have of something being imported that will cause issues.